Frequent on-off service Processes where the ''instantly'' large flow is needed.
Cannot be used for pressure control
Cavitate at low pressure drops
Cannot be used for throttling
Little resistance to flow
Usually made of ASTM A439 D2, for large size of valves rolling bearing is fitted at the two sides of the stem nut in order to minimize the open and close torque of valve.
Handwheel or Gearbox is usually used for gate valve actuation. The chain wheel, pneumatic cylinder, and electric actuator can be also used for the valve actuation if being requested by customer.
Stainless steel + flexible graphite spiral wounded gasket is used for 150 to 600 class, ring joint gasket is also optional for class 600 valves, for class 900 and above pressurized seal design is used.
Die molded pure graphite rings with top and bottom ring of brained graphite with Inconel wire reinforcement
BOBY BONNET CONNECTION
The body&bonnet between cass 150 to 600 bolted bonnet for 900 and above pressure seal design.
Stems are non-rotating with a surface finish to maximize packing seal for low fugitive emissions.
All our gate valve have back seat design, carbon steel valves are fitted with the removable back seat for stainless steel integral machined with a bonnet.
Seat faces lapped for a smooth finish and superior sealing. Optional renewable threaded seats or welded seats are as per customer specifications.
Flexible wedge for improved seating ease of operation, especially in high temperature service, wedges are accurately guided thru the entire stroke
Bolted Bonnet / Pressure Seal Bonnet
Gland Seal Design (Water Seal) With Lantern Ring
With NACE MR 0175
Gear / Pneumatic Cylinder / Hydraulic
Flexible / Solid Wedge / Double Disc Type
Cylinder / Electrical Actuator Operated
Extended Bonnet design for low temperature and cryogenic services.